The objectives of this proposal focus on computational studies of cooperative structural transitions and low-frequency dynamical processes in proteins. Specific goals include 1) Investigation of the energetics of Beta-sheet folding in proteins to determine the relative role of backbone-conformational energy minimization, extended hydrogen bonding interactions, and side-chain packing interactions in defining the final folded configuration, 2) Analysis of the correlated dynamical behavior of such systems which arise as a consequence of extended coupling interactions, and their relationship to cooperative structural transitions in proteins, 3) Computation and analysis of the structural and energetic properties giving rise to symmetrical arrangements of Alpha-helices, 4) Investigation of the effects of correlated dynamic behavior on the apparent geometrical and temperature factor behavior of refined protein structures, and 5) Investigations of refinement methods which incorporate physically realistic approximations of dynamical coupling in proteins.